[IMP] account, portal, *: Move pager in breadcrump

*project/purchase/sale/website_quote

Before this commit:
Some module having a portal page (Quotation, SO, Purchase..) would display a
pager in the page, sometimes on the document header, sometimes in the middle
of it.
Every template would have to t-call the `portal.record_pager`.

Now:
The generic portal breadcrump will now display the pager directly on the top
right. It means every portal template setting `prev_record` and/or
`next_record` will automatically have the pager displayed without having to
call it.
Plus, it will be displayed at the same position for every template, making
the behavior more consistent.

Plus, it will also remove the background color from the breadcrump and hide the
home button when you are already on the home page.

opw-39876